Circuit breaker with disconnect



Dec. 25, 1951 w LEEDS CIRCUIT BREAKER WITH DISCONNECT 5 Sheets-Sheet 1fig 2.

Original Filed June 25, 1946 I Ju/Qf/bn 7 Z w w /A/// may 2 m y z a? .725 5 W vr\ p .3 v \n I 1% a y a n I 7/// z a w 4 INVENTOR Dec. 25, 1951 wM, LEEDS CIRCUIT BREAKER WITH DISCONNECT I5 Sheets-Sheet 2 OriginalFiled June 25, 1946 min] INVENTOR Mhfhrop/V/fleeofi. Q BY X/ ATTORN Dec.25, 1951 w LEEDS CIRCUIT BREAKER WITH DISCONNECT 3 Sheets-Sheet 3Original Filed June 25, 1946 INVENTOR Mh/hrop M Z sea 5.

ATTORNEY Patented Dec. 25, 1951 CIRCUIT BREAKER 'WITH ,DISCONNECTWinthrop M. Leeds, Pittsburgh, Pa., assignor to Westinghouse ElectricCorporation, East Pittsburgh, Pa., a corporation of PennsylvaniaContinuation of application Serial No. 679,087, June 25, 1946. Thisapplication July 8 1949,

Serial No. 103,683

18 Claims. i.

This invention relates to circuit interrupters, in general, and moreparticularly to are extinguishing structures and disconnect meanstherefor.

This is a continuation of my application, filed June 25, 1946, SerialNo. 679,087 now abandoned and assigned to the assignee of thisinvention.

Circuit interrupters are not only used in a transmission system or otherelectrical network for disconnecting normal loads or for line droppingoperations, but they are also used to provide protection during theexistence of faults on the line. For example, a line may be broken andfall to the ground, thereby imposing a very high short circuit upon thesystem. The circuit inter rupter must be designed to disconnect thatflow of power from such a grounded line. It is apparent that in such acase if the circuit interrupter were reclosed, the fault would stillexist upon the line.

However, it may occur that lightning will strike a transmission line andcause current to flash over one or more suspension insulators associatedwith the line. In such a case the passage of a considerable amount ofcurrent over the insulator to the ground will temporarily cause aportion of the line to be at ground potential. Since a portion of theline would then be at ground potential, short circuit current would flowwhich would cause the opening of the circuit interrupter. If, now, thecircuit interrupter is reclosed, the ionized path over the insulatorswill have disappeared by this time andservice will be restored. Thus, inorder to maintain continuity of service to the consumer using currentfrom such a system, it is desirable to have the circuit interrupterimmediately reclose following a fault condition. If, as in the firstcase mentioned above, the transmission line actually has broken and ispermanently at ground potential, no number of reclosing operations willsuflice to restore service. Thus, after a predetermined number ofreclostng operations the circuit inter rupter is locked open and remainsopen until the station attendant investigates the matter to remedy thefault condition.

Should, however, lightning have struck the transmission line and merelyflashed over the insulation, service may be restored inasmuch as thefault condition is only temporary. It is thus with the hope of thereexisting merely a momentary fault condition that reclosing operationsare provided in a circuit interrupter. It is to be observed, however,that if the fault condition still exists, there may occur arcing as thecontacts approach one another during such closing operation. Thisresults inasmuch as one/side of the interrupter will be at groundpotential;

whereas the other side of the interrupter may be Such arcing followingpre-- striking during the closing stroke as the con-:

at a high potential.

tacts near one another tends to contaminate the oil or fluid within theinterrupter for the next reopening operation.

There is no way for the circuit interrupter to know whether the faultcondition is permanent,

as is the case with a broken line, or whether the.

fault condition is momentary, as is the case with lightning flashingover the transmission line insulation. Thus, reclosing operations arerequired in all cases in the hope that in many of the cases the faultmay be momentary and service immediately restored to the consumer.

Immediately following the interruption of an are in an arc extinguishingunit, an appreciable time interval must elapse before contaminating gasis completely vented and the arcing spaceand greater are energy in thesecond interruption that follows immediately.

My invention provides an uncontaminated series gap of high dielectricstrength regardless of the condition of the interrupting chamber so thatprestriking on reclosing will be negligible.

Excessive prestriking will also be avoided on normal closing operationsif the arc extinguishing chamber should develop carbon-coated creepagesurfaces due to repeated duty without adequate maintenance.

It is desirable for simplification in circuit breaker design andreduction inmaintenance expense to reduce the number of seriesinterrupters per pole, but this results in an increase in the voltagegradient in the contact gap. This would make excessive prestriking ofthe arcmore likely to occur on rapid reclosing duty cycles. Suchprestriking tends to reduce the eifectiveness of the interrupter for asubsequent immediate arc interruption. My invention concerns numerousdesign features which are desirable to obtain maximum interruptingeifectiveness in a high voltage circuit breaker, especially adaptablefor circuit breakers of the liquid break type, having high speedreclosing duty cycles.

A general .object of my invention is to provide an improved circuitinterrupter in which interruption of the circuit takes place within anarc 3 extinguishing unit, during which time the serially-relateddisconnect means remains closed. Following interruption of the circuitwithin the unit, opening of the disconnect means then takes place.

Another object is to provide an improved circuit breaker including twoserially related arc extinguishing units. Preferably I eflect reclosureof the contact structure within the units following opening of thecircuit, so that during the closing operation the two isolating gaps arecooperable to hold considerable voltage during such closing operation.

Another object is to provide an improved circuit interrupter having aconducting cross-bar electrically interconnecting an arc extinguishingunit and serially related disconnect means. Preferably the conductingcross-bar includes a pivoted blade so that the disconnect means remainsclosed while the circuit is broken within the arc extinguishing unit.

Another object is to provide an improved circuit interrupter of the typehaving disconnect means in series with the arc extinguishing unit and inwhich a movable disconnect contact moves during the opening operation tothereby maintain the circuit closed at the disconnect means while it isbeing broken within the unit. Preferably means are included forretrieving the movable disconnect contact following opening of thedisconnect means.

Another object of my invention is to provide an improved circuitinterrupter of the single bushing type in which the contact structurewithin the arc extinguishing unit is reclosed following a circuitopening operation. Consequently, the circuit is reclosed exteriorly ofthe unit so that the fluid within the unit cannot become contaminated asa result of prestriking.

Another object is to provide an improved arc extinguishing unit havingdisconnect contacts serving the function of opening the contactstructure within an arc extinguishing unit. The interconnection betweenthe disconnect contacts and the contact structure within the unit may beeither positive and released by cam action, or the interconnection maybe merely frictional in nature.

Further objects and advantages will readily become apparent from thereading of the following specification taken in conjunction with thedrawings, in which:

Figure 1 is a side elevational view, partly in section, of a circuitinterrupter embodying my invention and shown in the closed circuitposition;

Fig. 2 is an enlarged vertical sectional view through the disconnectmeans employed in the interrupter shown in Fig. 1;

Fig. 3 is a plan view of the latch head employed in Fig. 2;

Fig. 4 is a modified type of disconnect means incorporating a pivotedblade construction, which may 'be used in place of the disconnect meansutilized in Fig. 1;

Fig. 5 is an enlarged end elevational view of the modified type ofdisconnect means shown in Fig. 4;

Fig. 6 shows a modified type of circuit interrupter involving an arcextinguishing unit which is reclosed following the opening operation;

Fig. '7 shows a modified type of frictional fin-- ger construction,which may be used in place of the finger construction employed in theunit shown in Fig. 6;

ill

Fig. 8 is an end elevational view of the finger construction actuallyused in the unit of Fig. 6;

Fig. 9 is an elevational view, partly in section, of a modified type ofcircuit interrupter embodying my invention, the parts being shown in theclosed circuit position;

Fig. 10 is an enlarged fragmentary view of the disconnect contactstructure used in the interrupter shown in Fig. 9;

Fig. 11 is an elevational view of the complete circuit interrupter ofFigs. 9 and 10, the interrupter being of the single bushing type; and

Fig. 12 shows a further form of circuit interrupter embodying myinvention.

Referring to the drawings, and more particularly to Fig. 1 thereof, thereference numeral 1 designates a tank filled to the level 2 with asuitable arc extinguishing fluid 3, in this instance circuit breakeroil. Depending from the cover 4 of the tank I, are two terminal bushings5, 6, to the lower ends of which are respectively appended an arcextinguishing unit 1 and disconnect means 8. Conducting means 9, in thisinstance comprising a conducting cross-bar l8, electricallyinterconnects the unit 1 and disconnect means 8 in series circuit in theclosed circuit position, as shown by the full lines of Fig. 1. Aninsulating operating rod II is connected to the cross-bar Itintermediate the ends thereof for causing actuation of the same in avertical direction. The operating rod H is connected at its upper end tosuitable mechanism, not shown.

The unit 1 is of the type which establishes a pressure-generating arcand an interrupting are substantially simultaneously. An operating rodI! which moves downwardly during the opening stroke with the lowermovable contact !3 rotates a pivotally mounted pressure-generatingcontact in a clockwise direction about the pivotal point l4 away from anintermediate contact, not shown, to establish a pressure-generating arewithin the unit I. The movable contact 13, during the opening operation,also separates substantially simultaneously from the intermediatecontact to establish an interrupting arc. Fluid flow under pressure,generated at the pressure-generating arc, passes through suitablepassages toward the interrupting arc to effect the extinction of thesame. The intermediate contact, the pressure-generating contact and thefluid flow passages are similar to those shown in Fig. 6 hereinafterdescribed.

The particular unit I of Fig. 1 is described and claimed in U. S. patentapplication, filed November 11, 1942, Serial No. 465,244, now U. S.Patent 2,406,469, issued August 27, 1946 to Leon R. Ludwig, Winthrop M.Leeds and Benjamin P. Baker, and assigned to the assignee of the instantapplication. Reference may be had to the aforesaid application for theinternal constructional details. For the purposes of this application,it is sufi'icient to state that the lower movable contact I3 separatesfrom an intermediate contact, not shown, substantially simultaneouslywith the separation from the intermediate contact of the upper pivotallymounted pressuregenerating contact, which is pivotally mounted at I4 andactuated externally of the unit I by integrally formed actuating armsI5, the latter being actuated by the insulating operating rod 12.

minal stud which passes interiorly through the terminal bushing 6. Amovable disconnect contact 1 8 has a latch head 19 integrally formedtherewith, the latter having a configuration more clearly shown in Figs.2 and 3. The latch head l3, as viewed in Fig. 3, is cut away on twosides 20 to the width of the stem 2| so that releasing action may takeplace upon rotative movement of the latch hooks 22. The latch hook-s 22are pivotally mounted on pins 23 to a cylindrical member 24, the latterhaving a flange portion 25 at its upper end. A retrieving compressionspring 23 has its upper end resting against the flange portion 25 andits lower end resting against an inwardly extending portion 21 of thehousing [5.

Integrally formed with the flange portion 25' are two ofistanding pins28, diametrically oppositely positioned, and movable in two curved camslots 29 machined on the interior surface of the housing [6, and onlyone of which is shown in Fig. 2. From the foregoing description, it willbe apparent that upon downward movement of cylindrical member 24 andcorrespondingly downward movement of the latch hooks 22, the pins 28'sliding in the two cam slots 29, will cause the latch hooks 22 to rotatesubstantially 90 aboutan axial direction to thereby effect release ofthe latch head I9. Thus, I provide a positive engagement between thelatch head l9 and the latch hooks 22 until such time as the cylindricalmember 24 is rotated to such an extent as to eiiect releasing engagementbetween the latch hooks 22 and the latch head it.

When this releasing action takes place, the movable disconnect contact 18 continues its downward movement independently of the latch hooks 22,which, together with the cylindrical member 24', are retrieved to theirupper position, as shown in Fig. 2, by the retrieving spring 26.

Preferably, I provide a cup-shaped movable disconnect contact 30, whichmakes good contacting engagement with the movable disconnect contact ['8by virtue of a compression spring 3| encircling a stud 32, and havingits lower end threadedly secured at 33 to the movable disconcontact 30.A stop cap 34 is secured to the upper end of the stud 32. A flexibleconductor 35' is secured to the stud 32 at one end and to a screw 36 atits other end, the screw 36 being threadedly secured into the contactfoot IT.

From the foregoing description, it will be apparent that the electricalcircuit through the interrupter passes downwardly through the terminalstud within the terminal bushing 5 and through the contact structureassociated with the unit 1, through movable contact 13, conductingcross-bar l0, movable disconnect contacts 18, 30, stud 32, flexibleconductor 35, screw 38, contact foot I! to the terminal stud (notshown), which is positioned interiorly of the terminal bushing 6.

To open the electrical circuit, suitable means (not shown) causedownward movement of the operating rod II to thus cause downwardmovement of the conducting cross-bar H]. The movable contact l3and-operating rod i2 move downwardly to thereby substantiallysimultaneously establish a pressure-generating arc and an interruptingarc within the unit '1. During this time, the latch hooks 22 makelatching engagement with the latch head Hi to thereby maintain theelectrical circuit closed at the disconnect means 8; Arc extinction and.consequent circuit inter rup'ti'on take place within the unit 1 inc.mannot set forth in the aforesaid Patent 2,406,469; Followinginterruption ofthe circuit, the cylindrical member -2-4" is moveddownwardly'suflicient 1y to effect rotationithereof to such an extentthat the latch hooks 22 ride onto the flattened portions 20 of the latchhead 19 to thus effect release of the movable disconnect contact 1 8.

The conducting cross-bar lflcarrie's the mov-- able contact 13 andmovable disconnect con-tact I8 with it; downwardly to the fully opencircuitposition of the interrupter, as indicated bythe- The' movablediscondotted lines 37 in Fig. :1. nect contact 3 0 is retrieved to itsupper position by its retrieving spring 25.

During the-closing operation, the movable-con" tact l3 enters the unit'1 to make contacting errgagement with the intermediate contact notshown). Substantially simultaneously, the cross-" bar l0 raises theoperating rod [-2 to rotate the pressure-generating contact (not shown)counterclockwise about the pivot 14 so that the pressure-generatingcontact strikes the intermediate contact atsubstantially the same timethat the movable contact l3 strikes the intermediate con tact to therebycomplete the electrical circuit through the unit 7. Substantiallysimultaneouslywith the closure of the contact structure assoc-i-- atedwith the unit' l, the movable disconnect con--' tact IB makesponta-ctingengagement with the movable disconnect contact 30, associated with thedisconnect means 8, the compress-ion spring 31 furnishing the requisitecontact pressure. Also the latch hooks 22 reen'gage the latch head 4-9;

From the foregoing description, it will be a parent that the electricalcircuit is completed at the unit 1 at substantially the same time it iscompleted at the disconnect means 8. Since the circuit at the disconnectmeans 8 closes through clear uncontaminated oil, the disconnect means" 8holds the voltage and thereby prevents exces sive prestriking within theunit 7. quently, should the interrupter be rapidly reclosed and thenimmediately reopened, the oil within the unit 1 is not contaminated byprestriking during the closing stroke; thus interruption during thesubsequent opening-operationis not deleteriously affected.

Figs. 4 and 5 show a modified disconnect means 41. The modifieddisconnect means "in cludes a conducting blade 42 pivotally mounted at43 to the cross-bar 1-0. A compression spring 44 has its upper seatagainst an ofifstanding "lug 45 secured'to the rod H, and its lower seatabout a pin '46 integrally formed with the blade '42. In the closedcircuit position, the blade 42 is'disposed between opposed disconnectfingers 41 the latter being biased inwardly by compression springs 48. Aflexible strap 49 has its ends riv eted to the upper ends of thedisconnect-fingers 41, and its center portion secured "by a bolt '53 tothe lower end of the foot I1. Studs I55 have their interior endsthreadedly secured to the disconnect fingers 41, and have stop caps 5.2:at their outer ends to limit the inward motion of the disconnectfingers 41 The compression springs 48 encircle the studs 5|. Thedisconnect fingers 41 are pivotally mounted on pins 53, which aresupported by downwardly extending portions 54 integrally formed with thefoot 51 rod, -H moves downwardly to eifect opening Consethe contactstructure within the unit 1 in a manner as previously described.Meanwhile the blade 42 rotates at 43 about the cross-bar It, the end 55thereof being held by frictional engagement at the disconnect fingers41. Finally, stop lug 56 strikes the lug 45, as shown byv the dottedlines in Fig. 4. Then, and then only, is the end 55 of the blade 42forced downwardly through the disconnect fingers 41 to separatetherefrom. When the blade 42 is free of the disconnect fingers 4'1, itsnaps to its lower position by reason of the compression spring 44.During the closing stroke, the blade 42 moves upwardly with theoperating rod II, the blade 42 being in its horizontal position. Thus,contact reclosure within the unit 1 takes place at substantially thesame time as contact engagement at the disconnect means 4|. The theoryof operation is the same as that set forth in the interrupter of Fig. 1,there being showngin Figs. 4 and 5, merely a modified type of disconnectmeans.

Fig. 6 shows a modified type of arc-extinguishing unit, generallydesignated by the reference numeral 51. The passage formation is of thetype set forth in the aforesaid Patent 2,406,469. The operating rod l2has a flange 58 secured thereto, at the ends of which are apertures 59.Studs 60 pass through the apertures 59 and have pressure springs 61encircling them. The upper end of each stud 60 is enlarged, as at 62,and makes pivotal connection at 63 to an actuating arm 64,

which is integrally formed with the rotatable pressure-generatingcontact 65. There are two such arms 64, but only one is shown in Fig. 6.The rotatable pressure-generating contact 65 makes engagement with anintermediate contact 66 in the closed position of the interrupter, asshown in Fig. 6. Cooperable with the intermediate contact 66 is a lowermovable contact 61, which is pivotally connected at 68 between a pair oflinks 69, the right-hand ends of which are pivotally connected at ill toa pair of links 1 l, the upper ends of which are pivotally mounted at astationary pivot 12. A pair of guide links 13 are pivotally connected at14 intermediate the ends of the links 69. The left-hand ends of theguide links 13 are pivotally mounted at '15 to the lower ends of a pairof lugs 16 integrally formed with the lower casting plate 11 of the unit'5. This linkage is designed so that pin 68, carrying contact 61, movesvertically along substantially a straight line.

The links 69 are pivotally connected, by means of a stud 18, to thelower end of the operating rod 12. The stud 18 also passes through apair of disconnect fingers 19, which make contacting engagement, in theclosed circuit position as shown in Fig. 6, with the conductingcross-bar Ill. The contacting portion 80 of the cross-bar l6, whichmakes engagement with the disconnect finger 19, has a configuration moreclearly shown in Fig. 8. Referring to this figure, it is to be observedthat the portion 80 is provided with shoulders 8|, which hook onlatching shoulders 92 integrally formed with the disconnect fingers l9.

' The disconnect fingers 19 are biased together by compression springs83 encircling the stud 18. A wedge 84 is mounted fixedly in place by anysuitable means, such as a strap connection 85, the strap 85 extendingbetween the lower walls 86 ofthe electrostatic shield 8'1. During theopening operation, after a predetermined downward travel of theoperating rod [2, the wedge 84 engages two pins 88 jutting outwardlyfrom the disconnect fingers T9 to thereby effect outward motion of thedisconnect fingers 19 to cause release of the contacting portion 80.Prior to the aforesaid releasing action, there is a positive gripbetween the cross-bar Ill and the disconnect fingers l9.

A retrieving compression spring 89, mounted at the upper end of theoperating rod [2 between a cap 96 secured thereto and a bracket 9|integrally formed with the top dome casting 92 of the unit 51, serves toreclose the contact structure within the unit 51 following release ofthe cross-bar H] by the disconnect fingers l9.

From the foregoing description, it will be apparent that in the closedcircuit position of the:

interrupter, partially shown in Fig. 6, the electrical circuittherethrough includes terminal stud.

93, contact foot 94, top dome casting 92, pressure-generating contact65, intermediate contact 66, lower movable contact 61 through a flexiblestrap to the disconnect fingers 19 to the conductingcross-bar ID. fromthe conducting cross-bar l9 through a similar interrupter assembly to asecond terminal stud (not shown).

To open the electrical circuit passing through the interrupter, theoperating rod H is moved downwardly by suitable means (not shown), tocause downward movement of the cross-bar 10. The downward movement ofthe cross-bar In, by the hooked engagement at BI, 82, forcibly pulls theoperating rod 12 downwardly. By the pivotal connections at 63 and 18,the lower movable contact 61 separates from the intermediate contactFollowing interruption of the circuit within theunit 51, the contact 61and linkage 69, 13 assume the position as shown in dotted lines in Fig.6, and the disconnect means are in the dotted line position of Fig. 8,at which time the pins 88 engage the wedge member 84 to cause releasebetween the disconnect fingers l9 and the crossbar 16. The retrievingspring 89 then immedi-- ately recioses the contact structure within theunit 51, and the cross-bar In continues downwardly to open a disconnectgap.

During the closing operation, the circuit is completed entirelyexternally of the units 51, thecross-bar it! making engagement at thedisconnect fingers 19. Thus, the circuit is completed through gapsinterposed in clear uncontaminated oil which are able to standconsiderable voltage and which minimize prestriking. Consequently, theoil within the unit 51 is not contaminated by prestriking and is in goodcondition for subsequent interruption, should immediate reopening of theinterrupter be desired. Certain features of my invention concerningclosing the circuit externally of the unit 5'! are described and claimedin United States patent application, Serial No. 548,815, filed August10, 1944, now United States Patent 2,456,926, issued December 21, 1948to James M. Cumming, and assigned to the assignee of the instantapplication.

In certain instances it may not be necessary to The circuit thenextends.

have a positive engagement between the crossbar I and the disconnectfingers I9, a's'impler frictional engagement being sufiicient, asillustrated by the disconnect contact structure shown in Fig. 7. In thedisconnect contact structure of Fig. 7, no wedge 84 is employed, theshoulders 06 at the contact portion 80 of the cross-bar I0 providing thenecessary holding action. When the contact structure is moved to itsfull open circuit position, the operating rod I2 is stopped in itsdownward movement by engagement of the cap 90 with the bracket 9|constituting stop means. At this time, the cross-bar I0 pulls free fromthe disconnect fingers 2'9 to interpose an isolating gap at thedisconnect contacts 79. After the cross-bar I0 pulls free of thedisconnect contacts I9, the retrieving spring 89 effects reclosure ofthe contact structure within the unit 51.

From the foregoing description of specific embodiments of my invention,it will be apparent that I have provided an improved circuit interrupterof the type especially adaptable for rapid reclosing service even whererelatively high voltage is encountered, prestriking being greatlyminimized by having the circuit closed through clean oil. In thestructure set forth in Fig. l, the contact tips in the grid and thedisconnect means are arranged to touch at approximately the same time.Even if the grid 1 is contaminated with gas, the clean oil break on theother terminal will hold voltage until the contacts are practicallyclosed.

In the aforesaid construction, practically no prestriking i obtained inthe grid to make additional gas that might interfere with the second arcinterruption. This means that all of the time between the interruptionof the first arc and the parting of the contacts during the second are,at least 20 cycles, will be available for getting rid of the gas in thegrid and replacing it with clean oil for the second operation.

When only one interrupting unit is used per pole, no resistors arerequired for the purpose of voltage distribution. In the arrangementwhere the contact structure in grid 57 is self-closing, two suchinterrupting units Would normally be used. Full terminal potential willbe brought down to the bottom of the grid assemblies when the mainmoving cross-bar i0 is in the full open position. This reduces thegradient on the insulation while the breaker is standing in the openposition without requiring the resistors used for the purpose as setforth in the aforesaid Patent 2,406,469. The elimination of the resistoris desirable to avoid the contaminating effect of the residual resistorcurrent being interrupted in the disconnect break. The arrangement setforth in Fig. 6 was tested successfully, opening 2000 amperesat 132300volts across two units 57 in series on a 2!) cycle reclosing duty cycle.This means a first interruption followed by reclosing of the breakerwithin an interval of 20 cycles, or second, after the initial trippingimpulse, followed by an immediate second interruption of the shortcircuit. Because of substantial elimination of prestriking during therapid 'reclosin opera ion, the second interruption 'Was practically aduplication of the first.

Figs. 9 through 11 show a furtherembodiment of my inventionincorporating certain design features, which are set forth and claimedin United States patent application, Serial No. 591,047, filed April 30,1945, 'now Patent No. 2,534,920, Dec. 19,1950. byLeon R. Ludwig and 10Benjamin P. Baker, and assigned to the assignee of the instantinvention.

Referring to Fig. 11, which shows the complete interrupter of thismodified type embodying my invention, the reference character 98designates a base, which supports vertical structural members 99 bracedby diagonally disposed members I00. The vertical structural memberssupport a platform IOI of structural steel, which is at ground potentialand. which supports in place a circuit interrupter of the single bushingtype, the interior of which is shown more clearly in Fig. 9,

The circuit interrupter is generally designated by the reference numeralI02. It consists of a single high voltage terminal bushing I03,preferably of the high voltage paper-wound condenser type. To the lowerend of the terminal bushing I53 is a guide I04, having diametricallydisposed guide slots I05 and being clamped to the lower end of theterminal stud I06 at I01. A movable disconnect contact I68 telescopeswithin the guide I 04 in the fully open circuit position of theinterrupter.

The movable disconnect contact I 08 is actuated by a pin I09, whichpasses therethrough, and to the ends of which are pivotally mounted apair of insulating operating rods H0. The operating rods Iii have theirupper ends mounted upon a pin IiI, which passes through the left-handend of a lever I I2 pivotally mounted upon astationary pivot I I3. Acompression spring I I4 serves to bias the lever H2 in a clockwisedirection toward the open circuit position.

An insulating cylinder I I5 supports at its lower end a supportingframework H6, which is described in the aforesaid Patent 2,534,920. Thesupporting framework IIB supports terminal mean ill, to which the lineterminal II 8 may be connected. The other terminal for the interrupteris designated by the reference numeral I I 9, and is disposed atthe-upper end of the bushing I03, through which the conducting meansI20, including the terminal stud 100, extends. The framework I I 5serves to support rigidly in place an arc-extinguishing unit 5'1, whichis of the type described in Fig. 6, but which is here inverted. Africtional disconnect means of the type set forth in Fig. 7 is employedfor effecting upward movement of the operating rod I2. The internalconstruction of the unit is the sameas that set forth in Fig. 6, and theoperation thereof is the same as previously described. In theinterrupter under discussion, the operation thereof is effected byclockwise rotation of the lever II 2, which moves the movable disconnectcontact I08 upwardly into the guide I04, the pin I09 moving upwardlyinto the guide slots I05.

Thus, in this embodiment of my invention, I show an improved circuitinterrupter of the single bushing type involving an arc-extinguishingunit having a reclosing contact structure disposed therein. In the opencircuit position of the interructer (not shown), the contact structureis reclosed within the unit 51, and the disconnect contact gap isentirely relied upon to hold the voltage. The circuit is closed during aclosing operation entirely at the disconnect contacts, the movabledisconnect contact I08 passing between the relatively stationarydisconnect contact fingers l9, as shown more clearly in Fig. 10. Thus,the circuit is closed exteriorly of the unit 5: to prevent contaminationof thefluidinfthe unit 5 due to prestriking.

Thus, in'Fig. 9, I haveshown novel mounting means fora circuitinterrupter employing a novel arc-extinguishing unit 51' of thereclosing type, in which prestriking is prevented during the closingstroke by closing the circuit exteriorly of the unit. Thus, duringreclosing operations, the fluid within the unit 51 has a longer timeinterval before a succeeding opening interruption to become free of gas,and at least partially replenished.

Fig. 12 shows a modified form of circuit interrupter embodying myinvention, in which a disconnect means 8 is suspended from the foot I!of a bushing 6 (not shown). serially related with the disconnect means 8is an arc-extinguishing unit 57 of the type set forth in Fig. 6. Theoperation of the unit 5'! is identical to that set forth previously inconnection with Fig. 6. However, in this form of my invention, I haveadded a flexib e conductor l2! connecting the cross-bar l and the lowermovable contact El.

During the opening operation, the operating rod I l is moved downwardlyto consequently cause downward motion of the cross-bar It. The contactstructure within the arc-extinguishing unit 51 is opened, and the arcsdrawn therein are interru ted in the manner described in connection withFig. 6. The disconnect contact structure 8 is extended and unlatched ina manner similar to that set forth in the discussion relating to thedisconnect means 8 of Fig. 2. The contact structure within the unitrecloses fol lowing unlatching of the contact portion 80 of thecross-bar in from the disconnect contact '59. There may merely befrictional contact between the contacting portion Bil of cross-bar itand the disconnect contact fingers E9 in a construction simi ar to thatset forth in Fig. 7. Following the unlatching of the disconnect fingersE9, the contact structure within the unit 51 is reclosed and the shuntl2! on the grid side puts all the voltage on the disconnect gap providedby the disconnect means 8.

During the closing operation, the final circuit is made at thedisconnect contacts 18, 30. The shunt l2l protects the latch onthe gridside from any arcing during the closing operation.

During rapid reclosing operations, the cross-bar Ill moves downwardlyfar enough for both the disconnect contacts I8, 36 and the contactingportion 80 of cross-bar ill and the disconnect fingers 19 to beunatched. Thus, during rapid reclosing operations, the circuit is madeat the disconnect means 8, the shunt l2! relieving the disconnectcontact fingers F9 from any arcing.

It will be observed that in the form of my in vention set forth in Fig.12 that I have provided an arc-extinguishing unit 5'! of the type inwhich the contact structure is reclosed following are interruption. Allarcing is removed from the latching surfaces of the cross-bar l0 anddisconnect contact fingers 19 by the provision of the flexible conductor52 l. The voltage is entirely relieved from the grid 5'! in the opencircuit position, and during the closing operation the circuit isentire- 1y made at the disconnect contact means 8 in a region of clear,uncontaminated oil to prevent prestriking.

Although I have shown and described specific structures, it is to beclearly understood that the same were merely for the purpose ofillustration, and that changes and modifications may readily be madetherein by those skilled in the art, without departing from the spiritand scope of the appended claims.

I claim as my invention:

1 In a circuit interrupter, an arc extinguishing un t ontact meansincluding a pivotally mounted pressure-generating contact, anintermediate contact and a movable contact, an operating rod pivotallymounted adjacent one end thereof to the pivotally mountedpressure-generating contact, disconnect means including a pair ofdisconnect finger contacts operatively connected to the other end of theoperating rod, linkage means interconnecting the other end of the rod tothe movable contact, a movable disconnect contact member for causinglimited folowing movement of the disconnect means, means biasing thecontact means closed to efiect contact closure following circuitinterruption, the movable disconnect contact member making latchingengagement with the disconnect finger contacts to cause said followingmovement of the disconnect finger contacts, means rel asing the latchingengagement following a predetermined opening movement of the operatingrod, and the circuit being made during the closing stroke at thedisconnect finger contacts.

2. A circuit interrupter of the liquid break type including a tank ofarc extinguishing liquid, a pair of terminal bushings extending withinthe tank, an arc extinguishing unit depending from the interior end ofone of the terminal bushings and immersed within the liquid, disconnectmeans secured to the interior end of the other terminal bushing,conducting means electrically connecting the arc extinguishing unit andthe disconnect means in series in the closed circuit Position, meanscausing the disconnect means to remain closed while the e ectricalcircuit is being broken in the arc extinguishing unit during the openingoperation, an insulating operating rod connected to the conducting meansintermediate the ends thereof to cause the actuation thereof,

and means causing the circuit to be made during the closing stroke atsubstantially the same time within the arc extinguishing unit as at thedisconnect means.

3. A circuit interrupter of the liquid break type including a tank ofarc extinguishing liquid, a pair of terminal bushings extending withinthe tank, an arc extinguishing unit depending from the interior end ofone of the terminal bushings and immersed within the liquid, disconnectmeans secured to the interior end of the other terminal bushing,conducting means electrically connecting the arc extinguishing unit andthe disconnect means in series in the closed circuit position, meanscausing the disconnect means to remain closed while the electricalcircuit is being broken in the arc extinguishing unit during the openingoperation, an insulating operating rod connected to the conducting meansintermediate the ends thereof to cause the actuation thereof, meanscausing the circuit to be made during the closing stroke atsubstantially, the same time within the are extinguishing unit as at thedisconnect means, the disconnect means including a pair of movabledisconnect contacts, and means effecting retrieving motion of one of themovable disconnect contacts in a direction away from the other movabledisconnect contact following opening of the disconnect means.

4. A circuit interrupter of the liquid break type including a tank of.arc extinguishing liquid, a pair of. terminal bushings extending withinthe tank, an arc extinguishing unit depending from the interior end ofone of the terminal bushings and immersed within the liquid, disconnectmeans secured to the interior end of the other terminal bushing, amovable contact movable completely out of the arc extinguishing unit in'13 the fully open circuit position of the interrupter, conducting meanselectrically interconnecting the movable contact and the disconnectmeans .in series in the closed circuit position, an insulating operating.rod secured to the conducting means intermediate the ends thereof tocause the actuation thereof, the disconnect means including a pair ofmovable disconnect contacts, means causing the pair of movabledisconnect contacts to move together during the initial portion of theopening operation while the circuit is being opened within the arcextinguishing unit, means eflecting the separation of the pair followingextinction of the are within the unit, and means effecting retrievingmotion of one of the pair of disconnect contacts in a direction awayfrom the other movable disconnect contact following seporation of thepair of movable disconnect con- 'tacts.

' 5. A circuit interrupter of the liquid break type "including a tank ofarc extinguishing liquid, a

pair of terminal bushings extending within'the tank, an arcextinguishing unit secured to the interior end of one terminal bushingand immersed within the liquid, disconnect means secured to the interiorend of the other terminal bushing and also immersed within the liquid,

conducting means electrically hiterconnecting the arc extinguishing unitand the disconnect means in series, an insulating operating rod'securedto the conducting means intermediate ends thereof to cause the actuationthereof, and

the

means maintaining the circuit closed at the disconnect means while thecircuit is being opened within the arc extinguishing unit during the initial portion of the opening operation.

6. A circuit interrupter of the liquid break type including a tank ofarc extinguishing liquid, pair of terminal bushings extending within thetank, an arc extinguishing unit secured to the interior end of oneterminal bushing and im mersed within the liquid, disconnect meanssecured to the interior end of the other terminal bushing and alsoimmersed within the liquid,

conducting means electrically interconnecting the arc extinguishing unitand the disconnect means in series, an insulating operating rod securedto the conducting means intermediate the ends thereof to causethe-actuation thereof, the disconnect means including a pair of movablevdisconnect contacts, means for effecting separation of the pair ofmovable disconnect contacts only following extinction of the arc withinthe are extinguishing unit during the opening operation, means forretrieving one of the pair or" movable disconnect contacts followingseparation 'of the pair of movable disconnect contacts, and

guishing unit in the fully open circuit position of .the interrupter,conducting means electrically interconnecting the movable contact inseries with the disconnect means, an insulating operating rod secured tothe conducting means intermediate the ends thereof to cause theactuation 31-4 thereof, the disconnect means including a pair of movabledisconnect contacts, means for effecting separation of the pair ofmovable disconnect contacts only following extinction of the are withinthe arc extinguishing unit during the opening operation, means forretrieving one of the pair of movable disconnect contacts followingseparation of the pair of movable disconnect contacts, and the point ofengagement of the pair during a subsequent closing operation beingdifferent than the point of separation thereof.

8. A circuit interrupter of the liquid break type including a tank ofarc extinguishing liquid, a pair of terminal bushings extending withinthe tank, an arc extinguishing unit secured to the interior end of oneterminal bushing and immersed within the liquid, disconnect means secured to the interior end of the other terminal rushing and alsoimmersed within the liquid, the disconnect means including a pair ofmovable disconnect contacts positioned externally of the unit,conducting means electrically interconnecting the unit and thedisconnect means in series in the closed circuit position, means forcausing the pair of movable disconnect contacts to be latched togetherso as to move together during the initial portion of the openingoperation, and means for releasing the pair of movable disconnectcontacts at a predetermined point in the opening operation followingextinction of the are within the arc extinguishing unit.

9. .In a circuit interrupter of the liquid break type, a tank filledwitharc extinguishing liquid, two terminal bushings projecting within thetank, means defining an arc extinguishing unit supported at the interiorend of one terminal bushing, disconnect means only supported at theinterior end of the other terminal bushing, a conducting cross-barhaving a portion thereof formed by a blade electrically interconnectingthe unit and the disconnect means, means pivotally interconnecting theblade to the crossbar, means for actuating the cross-bar and blade, andthe blade being pivoted during the opening operation so that thedisconnect means remains closed While the circuit is broken within thearc extinguishing unit.

10. In a circuit interrupter of the liquid break type, a tank filledwith a liquid, two terminal bushings extending into the tank, an areextinguishing unit depending from the lower end of one terminal bushing,disconnect means suspended from the lower end of the other terminalbushing, and a conducting cross-bar electrically cross-bar electricallyinterconnecting the unit and the disconnect means in the closed circuitposition, an operating rod connected to the crossbar intermediate theends thereof for causing actuation of the same, means for maintainingthe circuit closed at the disconnect means during the time the circuitis being interrupted within the unit, and means effecting reclosure ofthe contact structure within the arc extinguishing unit followingopening of the disconnect means.

12. In a circuit interrupter of the liquid break type, a tank filledwith are extinguishing liquid, two terminal bushings projecting withinthe tank, an arc extinguishing unit supported at the interior end of oneterminal bushing, disconnect means only supported at the interior end ofthe other terminal bushing, a conducting cross-bar electricallyinterconnecting the unit and the disconnect means in the closed circuitposition of the interrupter, contact structure associated with the unit,means for effecting reclosure of the contact structure Within the unitin the fully open circuit position of the interrupter, means formaintaining the circuit closed at the disconnect means during the timethe circuit is being interrupted within the unit, and a permanent shuntconnection between the cross-bar and the contact structure.

13. In a circuit interrupter of the liquid break type, an arcextinguishing unit immersed in liquid, contact structure within the unitincluding a pressure-generating contact, an intermediate contact and amovable contact cooperable to establish two serially related arcs, anoperating rod operatively connected to the pressuregenerating contact atone end, a pair of disconnect fingers operatively connected to the rodadjacent its other end, a disconnect member making engagement with thedisconnect fingers in the closed circuit position to cause actuation ofthe operating rod, means interconnecting the movable contact and theoperating rod, means biasing the operating rod to its closed circuitposition to effect contact closure following circuit interruption, andthe disconnect member separating from the disconnect fingers in thefully open circuit position of the interrupter to insert an isolatinggap in the circuit.

14. In a circuit interrupter of the liquid break type, a tank filledwith a liquid, two terminal bushings extending into the tank, an arcextinguishing unit depending from the lower end of one terminal bushing,disconnect means suspended from the lower end of the other terminalbushing, a conducting cross-bar electrically interconnecting the unitand. disconnect means in the closed circuit position, contact structuredisposed within the unit separable to draw an arc, means maintainingelectrical engagement at the disconnect means while the contactstructure is separated within the unit to establish an arc, and meansfollowing opening of the disconnect means for reclosing the contactstructure within the unit.

15. In a circuit interrupter of the liquid break type, a tank filledwith are extinguishing liquid, two terminal bushings projecting withinthe tank, an arc extinguishing unit supported at the interior end of oneterminal bushing, contact means including an operating rod forestablishing a pressure-generating arc and an interrupting are withinthe unit, disconnect means only supported at the interior end of theother terminal bushing, a conducting cross-bar for electrically bridgingthe unit and the disconnect means in the clo ed circuit position, thecross-bar and the operating rod initially moving together during theopening operation, means efiecting the release of the cross-bar from theoperating rod, and biasing means for effecting retrieving movement ofthe operating rod following actuation of the releasing means to reclosethe contact means within the unit.

16. In a circuit interrupter, an arc extinguishing unit, contact meansincluding a pivotally mounted pressure-generating contact, anintermediate contact and a movable contact, an operating rod pivotallymounted adjacent one end thereof to the pivotally mountedpressure-generating contact, disconnect means including a pair ofdisconnect finger contacts operatively connected to the other end of theoperating rod, linkage means interconnecting the other end of the rod tothe movable contact, a movable disconnect contact member for causinglimited following movement of the disconnect means, and means biasingthecontact means closed to efiect contact closure following circuitinterruption..

.17. In a circuit interrupter of the liquid break type, a tank filledwith are extinguishing liquid, an arc-extinguishing unit, means forimmersing the-arc-extinguishing unit in the liquid, contact structureseparable to establish an arc within the unit, relatively stationarydisconnect contact means, actuating means for causing the separation ofthe separable contact structure including the relatively stationarydisconnect contact means, a movable disconnect contact member makingengagement with the relatively stationary disconnect contact'means inthe closed circuit position of the interrupter, means for moving themovable disconnect contact member through the liquid away from the unitduring the opening operation to provide an isolating gap in liquid inthe fully open circuit position of the interrupter, means providing ashort following movement of the relatively stationary disconnect contactmeans with the movable disconnect contact member during the initialportion of the opening operation to cause thereby operation of theactuating means and consequent separation of the contact structure, andmeans biasing the contact structure to the closed position followingdisengagement of the movable disconnect contact member from therelatively stationary disconnect contact means so that the electricalcircuit may be closed exteriorly of the unit during the closing stroke.

18. In a liquid break circuit interrupter, an arc-extinguishing unit,means for immersing the unit in an arc-extinguish ng liquid, contactstructure separable to establish an are within the unit, actuating meansfor causing the separation of the contact structure, a movabledisconnect contact member movable away from the unit in the fully opencircuit position of the interrupter to provide a disconnect gap inliquid, means providing limited following movement of the actuatingmeans with the movable disconnect contact member during the initialportion of the opening operation to cause th'ereby separation of thecontact structure and establishment of an are within the unit, meansbiasing the contact structure to the completely closed circuit positionfollowing disengagement of the movable disconnect contact member fromthe actuating means, and the circuit being closed exteriorly of the unitduring the closing stroke.

WINTHROP M. LEEDS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Cumming Aug. 2, 1949

